# HG changeset patch
# User Valentin Bartenev <vbart@nginx.com>
# Date 1365778953 0
# Node ID 6362bd26e4b0332fa4f001278ad6fceb0cca596c
# Parent  f6bbe77794aa5882d097d94df38ecd2926d0964a
Events: protection from stale events in eventport and devpoll.

Stale write event may happen if read and write events was reported both,
and processing of the read event closed descriptor.

In practice this might result in "sendfilev() failed (134: ..." or
"writev() failed (134: ..." errors when switching to next upstream server.

See report here:
http://mailman.nginx.org/pipermail/nginx/2013-April/038421.html

diff --git a/src/event/modules/ngx_devpoll_module.c b/src/event/modules/ngx_devpoll_module.c
--- a/src/event/modules/ngx_devpoll_module.c
+++ b/src/event/modules/ngx_devpoll_module.c
@@ -343,7 +343,7 @@ ngx_devpoll_process_events(ngx_cycle_t *
     ngx_fd_t            fd;
     ngx_err_t           err;
     ngx_int_t           i;
-    ngx_uint_t          level;
+    ngx_uint_t          level, instance;
     ngx_event_t        *rev, *wev, **queue;
     ngx_connection_t   *c;
     struct pollfd       pfd;
@@ -510,7 +510,13 @@ ngx_devpoll_process_events(ngx_cycle_t *
                 ngx_locked_post_event(rev, queue);
 
             } else {
+                instance = rev->instance;
+
                 rev->handler(rev);
+
+                if (c->fd == -1 || wev->instance != instance) {
+                    continue;
+                }
             }
         }
 
diff --git a/src/event/modules/ngx_eventport_module.c b/src/event/modules/ngx_eventport_module.c
--- a/src/event/modules/ngx_eventport_module.c
+++ b/src/event/modules/ngx_eventport_module.c
@@ -551,7 +551,7 @@ ngx_eventport_process_events(ngx_cycle_t
                 } else {
                     rev->handler(rev);
 
-                    if (ev->closed) {
+                    if (ev->closed || ev->instance != instance) {
                         continue;
                     }
                 }